It is estimated that 220,000 people suffer cardiac arrest each year in the US, of whom only 10,000 survive to hospital discharge. The number of survivors could increase 10-fold if paramedical attention and/or defibrillation were available within a few minutes of the attack. It is the goal of our company to develop and deploy new and innovative technology that improves survival of cardiac arrest by lessening the time to treatment. This is a proposal to design, develop, and test the feasibility of an implanted monitor that notifies bystanders and emergency medical services (EMS) of an incipient cardiac arrest and/or acute myocardial iischemia. Such notification can shorten materially the time to defibrillation of most witnessed, and all unwitnessed, episodes of cardiac arrest, thereby improving survival manyfold. The tiny device will automatically detect the lethal event and signal transcutaneously to a cellphone in a purse, or pocket, or belt-worn or night stand unit which gives voice instructions to bystanders, spouse, or other witnesses and transmits victim location to the nearest EMS. Candidates for the implanted device are those readily identifiable cardiac patients whose medical condition and/or history puts them at particularly high risk of cardiac arrest. The work will include testing on the bench and in laboratory animals. After the device has been shown to be safe, it will be implanted in a small group of patients for use under realistic conditions.